PGI2 synthesis

Further evidence for the involvement of vitamin E in arachidonic acid metabolism comes from work by Valentovic, Gairola and Lubawy [146], who showed that vitamin E deficiency in rats increased hepatic lipid peroxidation and decreased aortic PGI2 synthesis. Inhalation of cigarette smoke by the rats increased platelet TXA2 by over 90% and reduced aortic PGI2 by between 26-33%. However, these effects were independent of the presence of vitamin E in the diet. 

Hypertension is associated with increased TXA2 and decreased PGE2 and PGI2 synthesis in some animal models, eg, the Goldblatt kidney model. It is not known whether these changes are primary contributing factors or secondary responses. Similarly, increased TXA2 formation has been reported in cyclosporine-induced nephrotoxicity, but no causal relationship has been established. 

Fig. 16.5 Pathways involved in VEGF-induced NO and PGI2 synthesis.

Nafazatrcxn ) inhibits 5- and 12-lipo>Q genases but not the cyclcxjxygenase of B16a tumor cells and also inhibits tumor proliferation. Other studies have shown nafazatrom increases PGI2 synthesis by aortic strips and has antithrombotic activity. 

Inhibits VSMC mitogens and matrix formation Stimulates endothelial cell repair Stimulates arterial endothelial cell PGI2 synthesis Facilitates metabolism of triglyceride rich lipoproteins Faciliates fibrinolysis... 

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